Protective helmets are commonly worn by people to shield their heads from flying or falling objects. The helmet usually has a rigid protective shell of an impact resistant material. For some applications, helmets have face shields attached thereto to protect the wearer's face. The helmet and face shield can form a protective enclosure to which is supplied uncontaminated air. Respirators are frequently combined with helmets and face shields to protect workers in areas where the air may be contaminated by toxic or noxious substances, such as particulates, gases and vapors.
Various government agencies and industry organizations define certain requirements and standards for protective gear, including helmets and respirators. For example, the National Institute of Occupational Safety and Health (NIOSH) certifies certain safety standards in the U.S. The American National Standards Institute (ANSI) recommends voluntary consensus industry standards. Other agencies and organizations around the world also establish safety standards for helmets and respirators. For protective helmets, some of the standards relate to impact energy attenuation, penetration resistance, force transmission, stiffness, flammability, electrical insulation, and head coverage.
The term "loose fitting face piece" defines a ANSI classification of a respiratory protective system in which the respirator enclosure is designed to form a partial seal with the face. Loose fitting face pieces do not seal on the neck and shoulders of the wearer and may or may not offer head protection against impacts and penetration. Positive pressure respiratory air supplied to such a system assists in forming a protective shield around the worker's face. A "loose fitting helmet" is another ANSI classification in which the respirator completely covers the head and neck, and may cover portions of the shoulders. Loose fitting helmets typically seal around the neck of the user. ANSI standards permit the use of "loose fitting face pieces" for exposures of up to 25 times the permissible exposure limit (PEL) for most contaminants. Loose fitting face pieces are typically not worn by users with facial hair. A loose fitting helmet can be used with up to 1,000 times the PEL, and may be used with facial hair.
Some workers may require multiple face pieces attached to a single helmet. Welding operations present a number of potential hazards to the welder that require the welder to use a specially designed protective device. Welding can cause sparks and hot metal debris to fly off the work piece. Welders often wear a clear face shield attached to a helmet to protect their head and face when the welding shield is raised. Welding can also generate toxic or noxious fumes requiring the welder to wear a respiratory system. Welding also causes high intensity light to be generated, requiring the welder to wear a darkened lens over their eyes to prevent eye damage.
Protective systems with the highest level of protection may not be optimum for a particular job that does not require that level of protection. For example, protective systems with a high level of protection can be heavy, may cause some discomfort to the wearer and can be costly. Although a loose fitting face piece system is lighter, less expensive, and more convenient than a loose fitting helmet, such systems are not acceptable for some applications. Therefore, many different types of helmets, respirators and face shields have been developed to meet the many different applications and standards that exist. Consequently, manufacturers have been forced to produce a variety of different systems for different conditions, as well as requiring users to stock and maintain many different systems. There is a need for a protective device that can be convertible between different production classifications.